This invention relates to photographic film and resin coated papers having improved antistatic properties, and to a method of producing such antistatic photographic film and resin coated paper. A continuing problem during the manufacture and use of photographic film and resin coated papers is that electrical charges tend to accumulate on them. These static charges are produced as a result of friction on the film or paper from rollers and other parts of the machines through which it passes during slitting or unwinding the film, by contact with dissimilar surfaces, by handling the film, and by various other causes which are familiar to those skilled in photographic art. Electrostatic discharges can also occur as motion picture film is transported rapidly through a camera or projector. When static discharge occurs in film prior to development, it is evident after processing as irregular streaks or patterns in the film. Processed film may accumulate electrical charges in like manner which causes it to accumulate dust, lint and various particles. The type of accumulation is particularly bothersome in the case of projection of slides or motion picture film as it results in distortion of the projected image, and occasionally, in permanent scratching of the film surface.
Many methods of diminishing the tendency to accumulate electrical charges on photographic film have been suggested. U.S. Pat. Nos. 2,074,647; 2,584,337; 2,649,374; 2,725,297; 3,399,995; 3,625,695; 3,630,742 discuss antistatic treatment using resins or polymeric compounds. Compounds of this type, although effective in improving the antistatic properties of the film are usually deficient in that the antistatic layer rubs off in use, and can cause undesirable accumulations of dust or flakes in the apparatus. It is also common for such antistatic compositions to form slurries or flocculent masses during processing thereby creating difficulties.
Polymers and copolymers such as those described in U.S. Pat. No. 2,074,647 are usually quite tacky and are subject to pick-off and flocking. This is particularly unsuitable in that during unwinding of the film base, prior to emulsion coating, since areas of pick-off can produce uneven coating, and when present in sigificant quantities actually increases static discharge. Emulsion-coated rolls which are treated with this type of antistatic polymer may present an undesirable physical appearance due to pick-off.
An object of the present invention is to provide photographic polymeric film supports, photographic films and polymeric coated photographic papers which have a minimum tendency to accumulate static charges. It is a further object of the present invention to provide photographic polymer film supports, photographic films and polymeric resin coated paper having improved antistatic properties and slippage characteristics.